1. Field of the Invention
The present invention relates to change-over of console terminals of service processor for fault detection and recovery, initial program loading of an information processing unit.
2. Background of the Related Art
A computer system comprising a central processing unit, a and main storage unit, a main storage control unit for accessing the main storage unit and a channel unit for controlling the input and output has been used for information processing and scientific calculation, etc.
A supercomputer to be installed in offices is connected with a service processor (hereinafter abbreviated as SVP). As described in the Japanese Patents of Laid-open Nos. 55-88157, 59-173815, 59-180734, the service processor conducts fault detection and recovery of the central processing unit, main storage unit and main storage control unit, for example, and follows the history or prior art of the instruction processings. Moreover, the service processor conducts the well known initial program loading as an important processing. The initial program loading means loads of necessary programs before the computer starts processing, but if the computer generates a system-down or system-failure due to a fault, it discontinues processing.
The service processor SVP is connected to a terminal unit for executing the intrinsic processing (e.g., fault detection and recovery, initial program loading) thereof, providing, a console and an operator is capable of inputting processing commands from this console. Moreover, an operating system (OS) stored in the main storage unit is tranferred to the central processing unit (CPU) and thereby the predetermined processing is executed by the computer system. The OS message is sometimes output to SVP from this operating system (OS). This operation is carried out by outputting the current condition of computer system to SVP.
In addition, SVP is sometimes connected with a plurality of work stations. The interface line is connected to SVP through an interface of channel unit and an output of a application program of computer system is output to work station WS through SVP. Moreover, it is possible to input determined data and command to the application program from WS.
In more detail, it is supposed here that 16 units, for example, are connected to SVP. A particular one unit of the sixteen is used executing the intrinsic processings of SVP (e.g., fault detection and recovery, initial program loading described previously). The remaining 15 terminal units are used as the work stations to execute the processings concerning the application program. Therefore, the unit used as the SVP is connected with the interface (signal line connected directly to CPU, main storage unit and main storage control unit, etc.) for intrinsic processing and the signal line outputs data of the application program to the display screen in order to input the command concerning the application program of the computer system.
As a plurality of terminals connected to SVP, the terminals for executing the intrinsic processing of SVP (hereinafter called an SVP terminal) and the terminals for application program (hereinafter called a WS terminal) are previously determined.
A total of 16 terminals are called from No. 1 to No. 16. Of these terminals, the terminal No. 1 is determined as the SVP terminal and the terminals from No. 2 to No. 16 are chosen as the WS terminals. These assignments of the terminals cannot be changed. Namely, when data is to be transferred to the terminal No. 1 or to the terminal No. 16 from CPU of the computer system, data is transferred together with information which designates the distant or target terminal number. Each function of the terminal which is previously stored in the program is stored in the main storage unit.
Therefore, alteration of the functions stored in the program is impossible unless the program is updated.
Usually, the necessary program is loaded before starting of the computer system during the initial program loading described previously. Specifically, the nucleus initial program is loaded and it is stored in the terminal No. 1, for example, whose terminal No. 1 is the SVP terminal. Accordingly, such a determination is already made before the computer system is started.
If a hardware fault (for example, display screen, CRT (Cathode Ray Tube) or LCD (Liquid Crystal Display) fails and display becomes impossible, or if a keyboard fails or microprocessor forming the terminal fails) occurs in the SVP terminal during operation of computer system, the intrinsic processing of SVP can no longer be continued. For instance, when CPU fails and it must be started again, namely when the initial program loading must be done, if the SVP terminal is defective or experiencing a failure, the processings by the computer system cannot be executed thereafter.
The SVP terminals are often installed in the area wherein the main frame of the computer system is also installed. In the case of offices or laboratories, a computer room is prepared and CPU, main storage unit, main storage control unit, channel unit and SVP are typically installed therein. The SVP terminals are installed in the computer room. The WS terminals connected to SVP are installed in the offices and laboratories for use by operators. In general, the computer room is physically separated from offices and laboratories. Therefore, when an operator recognizes a system-down or failure of the computer during use of the WS terminal, the operator must go to the computer room and conduct initial program loading by operating the SVP terminals to re-initialize the computer. Namely, an operator must go to the computer room from his current position and thereby the initial program loading is delayed. Currently, the computer system also deals with the processings including recording, calculation and simulation of changes of stock prices. Stock prices usually change from time to time in the matter of seconds. If initial program loading is delayed, it is no longer possible to correctly continue the procesings carried out. Such use of computer system is not limited only to stock prices but is also applicable to the computer system dealing with data which changes with the time, such as weather data or data transmitted from satellites.
It is a matter of course that a similar problem is generated even if the SVP terminal fails when the computer system fails and restarting must be done, when the initial program loading must be done.
Usually the same type of terminals are often used for the SVP and WS terminals and sometimes the same hardware of terminal itself may be used for both the SVP and WS terminals. The Japanese Patent of Laid-open No. 59-173815, "Console Work Station Change-over System" discloses a structure that the interface of a work station terminal is connected with the interface of an SVP terminal with a connecting line, a switch is provided between these interfaces and the terminal is connected to this switch. These terminals are changed over or converted to the work station terminal and SVP terminal with the switch. However, this switching is considered or preferred based on the computer system which is different from the system described above. Namely, the interface of SVP is so structured as allowing connection of one SVP terminal from the beginning, the interface for the work station is provided separately and such an interface is switched for one terminal with a physical switch. However, in this method, when a terminal is used as the work station, the SVP terminal does not exist or cannot be used. Therefore, a particular one terminal is switched from the WS terminal to the SVP terminal but it is impossible to freely select the SVP terminal from a plurality of terminals. If it is required to switch a plurality of terminals, it can be done by providing a plurality of switches the amount of hardware increases remarkably. Thus, the increased hardware is a disadvantage for realization of low cost computer system. An additional problem is that the SVP terminal is not recognized by the CPU. That is, the SVP terminal is not stored in the main storage unit. Therefore, if an operator changes over the switch when CPU starts the transfer of data to SVP or WS, the data transfer cannot be carried out correctly.
The Japanese Patent of Laid-open No. 59-180734 entitled "Common Use of System Console and Work Station" discloses the switching of a particular unit as the SVP terminal or WS terminal among a plurality of terminals connected to SVP. This technique realizes that terminal which is the SVP terminal is stored in the main storage unit but the particular unit which can operate as an SVP terminal can also be used as the WS terminal. Namely, a particular terminal unit can be used as the SVP terminal or WS terminal through the switching operation but the other terminals can be used only as the WS terminals.
Therefore, it is desired that the WS terminals among a plurality of terminals connected to the SVP be used also as the SVP terminals.